But you can't cascade windows or assymetrically resize child windows... that seriously changes how custom windows would work, since if they were not shown on the desktop they would *have* to be sized to fit the exact cell size of the user's grid layout, making the borderless/non-resizable @windows impossible to use. Of course this applies to resizing of regular windows as well.
I know you specifically do a lot of custom window work, so I'm surprised you would find this beneficial.